Tandem dual C(sp3)-H/C(sp2)-H functionalization: a radical cyclization of 2-isocyanobiphenyl with ether to 6-alkylated phenanthridine
作者:ChangDuo Pan、Jie Han、Zhu ChengJian
DOI:10.1007/s11426-014-5118-7
日期:2014.8
A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformation, which comprised the functionalization of two C-H bonds: the sp3 C-H of ether and sp2 C-H of phenyl group. The kinetic isotope effect (KIE) revealed that the cleavage of sp3 C-H bond would be involved in the rate-determining step.
rapid microwave-assisted approach for the synthesis of phenanthridine derivatives from the radical insertion/cyclization reaction of biphenyl isocyanides with a C(sp3)–H bond adjacent to a heteroatom has been developed. The protocol achieves wide substrate scope and good to excellent yields. The kinetic isotope effect (KIE) studies, radical inhibition studies, and Hammett plot analysis clearly disclose